Question for the new coil testers

[CA Steve]

In your opinions, what would be the difference in performance between the elliptical 18.75 coil and the new 6" 18.75. Besides the ground coverage and target seperation.

 

[Digger]

Depth of detection and sensitivity would be the only other things I can think of. When you are comparing two DD coils of the same frequency, for the same detector, there isn't much to compare other than depth of detection, sensitivity to small targets, ground coverage and target separation. Naturally, the larger coil will cover more ground and, due to the larger electromagnetic field, detect deeper. The smaller coils should be more sensitive to small (shallower) targets and the separation will be more precise. HH Randy

 

[wpaxt]

He pretty much summed up the differences. Choice of coil will depend on what you want to use it for.

Bill

 

[BarnacleBill]

1. The smaller size allows work around in smaller spaces i.e. heavy brush, rocks, boulders, playground equip. etc.
2. These coils are very ruggedly built, much more so than the elliptical.
3. They are made to be waterproof and much less buoyant than the elliptical. The elliptical could use a good dose of silicone just to be sure, ask Tinfoil how, he's the RTV King.
4. The small MF will fit all three X-Terra models.

HH
BarnacleBill

 

[Tinfoil]

You forgot to say hunting in the iron trash for the small concentric or the small DD. Never forget about the IRON TRASH. Thats where we diehards hunt. I don't know what to do if it is a clean area. Would one of you guys teach me how cause, it has been so long ago I don't remember what it is like. Do I use a big coil cause, if I do I will probley have to buy one or tare up the house looking for it. I think all the original ones that came with the machines will all be in the same place but, where did I put them??? : : . Man I will be glad to get that 18.75 DD small coil. Already called Ronny and said the first one he gets is mine. Da Check will be in Da mail. : : All us old guys got to stick together cause, the young ones out number us. Just remember."Age and Treachery Always Wins Over Youth and Vigor. . Ok back to Lurking : : . Maybe one day I will get on here and say everyone that is a Lurker that reads one of my Posts will have to Post a responce just to see how many Lurkers are out there. What do you think???? Sort of like we say down here in the South, " If Ya'll can't stop and talk, then Ya'll just as you go by. ". HH Jerry aka Tinfoil

 

[Digger]

Ya can accuse me of a lot of things... ... but I've never been a lurker!

I also like having a wide variety of accessory coils for each of my detectors. Unfortunately for me, all you other guys comments convinced Minelab that 7.5 and 18.75 were the way to go on the first set of small ones. But, from what I've seen, either of these will be a good choice!

I've never had much luck with the shooter on my XLPro. For my moderate soil, I prefer the snooper or 5.3 instead. But if the small DD works well for you on your other machines, you are going to be plumb tickled to death with this one!!! HH Randy

 

[bfodnes]

Will that say that there may be a 3 khz small coil too....maybe...

 

[Digger]

n/t

 

[bfodnes]

n/t

 

[BarnacleBill]

n/t

 

[bfodnes]

I did not know that there is used more wire on lower frequenzies.

Dont think Minelab will give up on the Terras easily though, maybe they do a DD at 7.5 then.

I wonder what they have in mind for the next few months at their development department.

 

[BarnacleBill]

Jerry I was raised up in a small town in the mountains, if you don't honk and wave people are just downright insulted, thinkin' you're being unsociable. Only good reason not to is if they let their dog stray over and kill your chickens for the fourth time.

HH
BarnacleBill

 

[BarnacleBill]

The 3khz 9 inch concentric is much heavier than the 7.5khz 9 inch concentric. In radio antenna usage if you cut the frequency in half, the length of the antenna wire needs to double. So for instance at 3.7 Mhz the band is noted as the 80 meter band because a full radio wavelength is 80 meters at that frequency, and a full wavelength antenna wire needs to be 80 meters long. If you change frequency to one that is half of that, 1.85 Mhz then this is now the 160 meter band as the wavelength has now doubled.

Whether there is a direct correlation to coils I can't say, as these are wound into a solenoid shape, and there is also a good deal of mutual inductance and capacitive coupling. There are ways to tune the circuit and use less wire, but you need a certain amount of surface area to really have it work optimally.

HH
BarnacleBill

 

[Tinfoil]

Lay a big bead all the way around the edge about half way down from the top of the edge. Now that you have some nice heavy beads of RTV reason being you want it to spread and get enough squeeze out up out of the coil so you don't have and voids. Voids is a another reason I use the red RTV easy to see them. Now that you got squeeze out all the way around the coil now all you got to do is smooth it all down wipe the excess off smooth it up all the way around where the edge of the coil cover and the coil meet. Check with a 4 pwr. magnifier to see if you got any voids. If you do spread some more RTV over the area push it in real good, smooth it up and let it dry. After it has dried go back over it with the magnifier and check again if you have any voids if you do apply again a little bead smooth it up. Let it dry and go back over it with magnifier till you don't have anymore voids. You never have to worry about taking the cover off or getting water in the coil or sand. All coils have the waterproof connectors just some of them have a bad job of sealing where the two halves are put together like the Joey coil, Exterra 5X10, whites 5X10, the 4X7 excellerator, 4x6 shooter coils. I have done it on all my hollow coils and have never had a leak or any problem. My coils are in and out of the water , fresh and salt all the time. : : OK Barnacle Bill and Digger I am back to Lurking and reading. I am glad you guys post a lot. Imagine what this forum would be like if I posted here a lot HH Jerry aka Tinfoil.

 

[Tinfoil]

Or that TR mode and balance it to the mineralized ground like they tell you to do on page 28. You are going to lock the G/B and use the GND REJ. area of the Dis. and adjust for ground mineralization for the TR mode. You will get some nice depth and you can really seperate the iron from the good targets due to the no motion of the TR mode. It will really suprise you. I like the 3.5 also but that 4X6 shooter will work like you won't belive in that Iron trash. You can snake that thing in and out and just use the tip to get the target. It gets more depth then the 3.5 for me. Now I use the 5.3 when it is less junky My ground runs around 50 to 60 down here on the Xterra 70. So my mineralization is like yours only mine has more of a salt salinity and sulpher content to the ground. Try that Ground Reject TR Mode you gonna like it. Just keep the coil right on the ground. TR mode don't like air. The SAt mode is a excellent one too. My 6000XLPRO is one of the best detectors I ever owned for the way I hunt. Love the thing. OK back to LURKING : : . Later and HH Jerry aka Tinfoil

 

[BarnacleBill]

I am sure that will help a lot of guys & gals head off trouble before it starts. Getting water in your coil can sure make you think your machine has gone plain loco.

HH
BarnacleBill

 

[Tinfoil]

n/t